The invention relates to a system for continuous monitoring of the electrical conduction of at least a portion of an AC power system, comprising at least one module comprising means for producing a DC current component between first and second points located respectively on first and second conductors of the power system, means for measuring the DC voltage component applied between these first and second points and means for detecting a conduction fault taking account of said DC voltage component, the means for producing a DC current component comprising a controlled rectifier and means for controlling the controlled rectifier.
State-of-the-art systems, notably the one described in the document EP-A-430,823, corresponding to US Pat. No. 5,150,057, do not take the possible presence of stray DC currents on the power system into account.